Flip cxxNativeAnimatedEnabled featureflag default to true (#57204)

Summary:

## Changelog:

[General] [Changed] - Flip cxxNativeAnimatedEnabled featureflag default to true

Reviewed By: javache

Differential Revision: D108323433

Author: zeyap

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsDefaults.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<061d668cf04041f4d3d2f48f11dc739f>>
+ * @generated SignedSource<<5f6861a5aa2d6024ad8d4c236652bf64>>
  */
 
 /**
@@ -27,7 +27,7 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun cdpInteractionMetricsEnabled(): Boolean = false
 
-  override fun cxxNativeAnimatedEnabled(): Boolean = false
+  override fun cxxNativeAnimatedEnabled(): Boolean = true
 
   override fun defaultTextToOverflowHidden(): Boolean = true
 

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlagsDefaults.h

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<8dfc52502bd539e5e43d547f895a6d33>>
+ * @generated SignedSource<<d0e19eae3c8e1f69383642a42172bb11>>
  */
 
 /**
@@ -36,7 +36,7 @@ class ReactNativeFeatureFlagsDefaults : public ReactNativeFeatureFlagsProvider {
   }
 
   bool cxxNativeAnimatedEnabled() override {
-    return false;
+    return true;
   }
 
   bool defaultTextToOverflowHidden() override {

packages/react-native/scripts/featureflags/ReactNativeFeatureFlags.config.js

@@ -72,7 +72,7 @@ const definitions: FeatureFlagDefinitions = {
       ossReleaseStage: 'none',
     },
     cxxNativeAnimatedEnabled: {
-      defaultValue: false,
+      defaultValue: true,
       metadata: {
         dateAdded: '2025-03-14',
         description:

packages/react-native/src/private/animated/NativeAnimatedHelper.js

@@ -71,6 +71,21 @@ let globalEventEmitterAnimationFinishedListener: ?EventSubscription = null;
 const shouldSignalBatch: boolean =
   ReactNativeFeatureFlags.cxxNativeAnimatedEnabled();
 
+// Schedules `API.flushQueue` after the current batch, replacing any pending
+// flush. On device `setImmediate` is a microtask; under jest's fake timers it's
+// a fake-timer entry that only `runAllTimers` drains — not `await` or
+// `advanceTimersByTime` — so the deferred flush wouldn't run before a test's
+// assertions. Flush synchronously in tests instead.
+function scheduleQueueFlush(): void {
+  clearImmediate(flushQueueImmediate);
+  if (process.env.NODE_ENV === 'test') {
+    // TODO: T275950736 - remove this path
+    API.flushQueue();
+  } else {
+    flushQueueImmediate = setImmediate(API.flushQueue);
+  }
+}
+
 function createNativeOperations(): NonNullable<typeof NativeAnimatedModule> {
   const methodNames = [
     'createAnimatedNode', // 1
@@ -116,8 +131,7 @@ function createNativeOperations(): NonNullable<typeof NativeAnimatedModule> {
         // details, see `NativeAnimatedModule.queueAndExecuteBatchedOperations`.
         singleOpQueue.push(operationID, ...args);
         if (shouldSignalBatch) {
-          clearImmediate(flushQueueImmediate);
-          flushQueueImmediate = setImmediate(API.flushQueue);
+          scheduleQueueFlush();
         }
       };
     }
@@ -137,8 +151,7 @@ function createNativeOperations(): NonNullable<typeof NativeAnimatedModule> {
         } else if (shouldSignalBatch) {
           // $FlowExpectedError[incompatible-call] - Dynamism.
           queue.push(() => method(...args));
-          clearImmediate(flushQueueImmediate);
-          flushQueueImmediate = setImmediate(API.flushQueue);
+          scheduleQueueFlush();
         } else {
           // $FlowExpectedError[incompatible-call] - Dynamism.
           method(...args);
@@ -190,9 +203,7 @@ const API = {
     invariant(NativeAnimatedModule, 'Native animated module is not available');
 
     if (ReactNativeFeatureFlags.animatedShouldDebounceQueueFlush()) {
-      const prevImmediate = flushQueueImmediate;
-      clearImmediate(prevImmediate);
-      flushQueueImmediate = setImmediate(API.flushQueue);
+      scheduleQueueFlush();
     } else {
       API.flushQueue();
     }

packages/react-native/src/private/featureflags/ReactNativeFeatureFlags.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<609451fd0a38e0f8eaf685e7cf534e27>>
+ * @generated SignedSource<<1de542d9c189f934f52fc258fd591b06>>
  * @flow strict
  * @noformat
  */
@@ -224,7 +224,7 @@ export const cdpInteractionMetricsEnabled: Getter<boolean> = createNativeFlagGet
 /**
  * Use a C++ implementation of Native Animated instead of the platform implementation.
  */
-export const cxxNativeAnimatedEnabled: Getter<boolean> = createNativeFlagGetter('cxxNativeAnimatedEnabled', false);
+export const cxxNativeAnimatedEnabled: Getter<boolean> = createNativeFlagGetter('cxxNativeAnimatedEnabled', true);
 /**
  * When enabled, sets the default overflow style for Text components to hidden instead of visible.
  */